The HD (high definition) motion picture cameras widespread today are only insufficiently suitable to be able to generate digital images with an aspect ratio of 2.35:1 (Cinemascope process) for film production. In accordance with the HD standard, these cameras record an image format of 16×9 so that, when spherical lenses are used, digital images are generated with an image format of 16×9, which corresponds to an image aspect ratio of 1.778:1.
These images can only be converted into the Cinemascope format in that substantial horizontal image portions are cut off at the upper and lower side of the image. However, this is associated with an unwanted reduction in the vertical resolution of the resulting image.
Whereas typically so-called anamorphic lenses with a squeeze of 2:1 are used in the Cinemascope process to squeeze a scene with an image ratio of 2.35:1 onto a 4×3 sensor (or onto a 35 mm film in analog processes), so-called semi-anamorphic optical systems, which do not correspond to the conventional standard and are therefore currently not available, would have to be used for the imaging of a corresponding scene on an HD sensor with an image format of 16×9. In addition to the costs required for the development of such lenses, images taken using such a semi-anamorphic lens would create a different impression than images taken with conventional anamorphic lenses so that the acceptance of such semi-anamorphic lenses is questionable.
Since the taking of images in the 4×3 format, optionally with anamorphic lenses for the generation of the Cinemascope format has been widespread both with analog and, in the meantime, with digital taking processes, for a long time, the further use of digital motion picture cameras with a 4×3 sensor and conventional anamorphic lens elements for the taking of films in the Cinemascope process is desirable.
Since, in the meantime, the HD format with an image format of 16×9 has become established for the storage and the playing back of digitally encoded films, the normally available standardized image recording units, for example in the form of hard disk recorders or tape recording devices, are also usually only suitable for the recording of digital images in the 16×9 format.
Starting from an identical number of horizontal picture elements of, for example, 1920 pixels per image both for the 4×3 format and for the 16×9 format, the problem thus results of how the larger data volume of a digital image present in the 4×3 format can be recorded and stored by a recording device working according to the HD standard. The problem furthermore occurs that, in accordance with the HD SDI standard (high definition serial digital interface standard), data transfer rates are only possible with which no full images taken in the 4×3 format can be transmitted in real time (>25 frames per second).
The same problems exist when images of a film typically present in 35 mm (4×3 format) scanned using a film scanner should be recorded using a conventional HD recorder without any quality loss, i.e. without any reduced image information.